C model CHT's

[Guest]

3 hours ago, N1395W said:

I'm not trying to steal Dev's thunder, but I happened to have a picture of my starter but not my alternator:

Andy,

It looks like the lower seal is not tucked into the formed aluminum groove?

Clarence

[Andy95W]

Good eye, Clarence!

That picture was taken a few years ago while doing some other maintenance.  I had the lower cowling loose and pulled slightly forward off the firewall.

[DXB]

10 hours ago, N1395W said:

I'm not trying to steal Dev's thunder, but I happened to have a picture of my starter but not my alternator:

No thunder stolen Andy - yours is better, with a piece of baffle material screwed in place - my shop did do this area but simply stretched the structural limits of RTV - it seems to work ok though.  

Boy it would help to mobilize the lower cowling to address the area between my alternator and crankcase- this would leave the doghouse really tight for the first time.  I'm gonna give it another shot next time I change my oil...

[mike20papa]

This area of the baffles is so commonly overlooked.  I used the wool material from AC spruce and worked it around alternator, starter and the very difficult oil line to the prop gov.

[DXB]

4 hours ago, mike20papa said:

This area of the baffles is so commonly overlooked.  I used the wool material from AC spruce and worked it around alternator, starter and the very difficult oil line to the prop gov.

That work around your alternator and starter looks very nice!   Mine will not be nearly so elegant in the end I fear.   Here's a job where my cowl closure mod definitely does not help!   Agree it would be easier if it weren't for that pesky oil line. Looks like you took off your bottom cowl for this nice work?

After reading the thread below, I am intimidated and will NOT be personally removing my bottom cowl:

 

[Guest]

8 hours ago, mike20papa said:

This area of the baffles is so commonly overlooked.  I used the wool material from AC spruce and worked it around alternator, starter and the very difficult oil line to the prop gov.

Piper used a lot of felt in the Comanche baffles against the crank case.  You might want to add safety wire to the 2 alternator bolts.

Clarence

[Hank]

1 hour ago, M20Doc said:

Piper used a lot of felt in the Comanche baffles against the crank case.  You might want to add safety wire to the 2 alternator bolts.

Clarence

Excellent suggestion! I found one lf mine loose in the bottom of the cowl while changing the oil one time . . . When did it fall out???

[Supercop0184]

I have the same heat problem on climb out. I have the LASAR enclosure mod as well. Heck the other day My Hottest got up to 390 before ever leaving the dang GROUND! WHAT GIVES! my Mech discovered that my Cowel flaps werent opening all the way. Maybe that had some to do with it. 

[Oscar Avalle]

I like to close the loop on issues so let me share with you my latest experience with my CHTs. They were on the high side, in hot weather they even reached 490! So i started to look into several different solutions proposed by many of you and here are the results:

 

a. Baffling: I added the baffling around the alternator and replaced the old doghouse with a new one. Results about a reduction in 10 degrees in CHTs. 

b. Cowling: I replaced the original mod with the ARI mod.  The impact was lower than expected (only about 10 degrees). I don't know if I gained any speed... but just for the looks... I don't regret at all having done the mod.

 

 

c. Ignition: I asked my AI to look at the ignition and indeed the timing was off by 5 degrees. This made a huge difference. I would say about 30 degrees. 

d. Carburetor : Overhauled and exchanged it. Fuel flow is better, but no impact on CHTs.

e. Checked for induction leaks. Everything ok.

f. Checked grounding JPI. OK

Any other ideas, suggestions?

Conclusion:

Due to the VERY HOT weather in the NE, I have not been able to compare the results with the baseline, but I feel that the cowling mod and the timing adjustment made a difference. So at least now I feel that I can push the engine more and climb at a reasonable climb rate, even in hot weather. The CHTs on climb out at 90 degrees F go up to 450 - 460 but once established they come down to 390 - 400. 

Oscar

 

[DXB]

Seems like you have very diligently done everything possible to run cooler.  Of course 490 is insane, but I think your present experience after all the work might confirm that C's just plain run hot with their primitive cowl design?

Still, something doesn't seem quite right with your temps.  I've been flying in the same weather and have touched 440 only once early in climb, and that was in the worst possible conditions (90's temps, long taxi, then having to clear a fouled plug before departure by leaning at high rpm on the ground).  By dropping the nose and climbing at 120mph ASAP, I can keep my temps <410 without a long taxi and <430 if there's a long wait on the ground in the nasty summer weather.  And it does just fine now in cooler temps after only limited baffle improvements.

Does your plane have have fixed or adjustable cowl flaps?  It's been suggested by my MSC that I get my fixed cowl flaps cracked open a bit more.  I am reluctant because I still think the baffling could be improved further first. Also I think that there's an adjustable cowl flap mod.

-humble PP, not A&P

[par]

Interesting that even after throwing all this money at the problem, it didn't go away and here I thought anything could be solved by throwing enough money at it. Perhaps some more money should be thrown at the mooney?

In all seriousness though, your plane looks much better with the cowling closed up and that pointy spinner. I have the same thing on mine and obviously, I like it. As far as CHT'S go, I have noticed lately even in this 95 degree heat wave that my hottest cyl (#3) has not gone past 420 in the climbout on the first takeoff of the day. All other cylinders remain 410 or below and will quickly cool off to the mid 300's after takeoff. However, if I go for my gas stop and takeoff within 10 mins of landing, I def see #3 reach 430-450. However, this is about the worst possible case I have observed. At this point, I may look at timing when I OH the mags next annual but until then, I'm just going to live with the problem.

 

Edited August 17, 2016 by par

[Marauder]

I like to close the loop on issues so let me share with you my latest experience with my CHTs. They were on the high side, in hot weather they even reached 490! So i started to look into several different solutions proposed by many of you and here are the results:

 

a. Baffling: I added the baffling around the alternator and replaced the old doghouse with a new one. Results about a reduction in 10 degrees in CHTs. 

b. Cowling: I replaced the original mod with the ARI mod.  The impact was lower than expected (only about 10 degrees). I don't know if I gained any speed... but just for the looks... I don't regret at all having done the mod.

 

 

c. Ignition: I asked my AI to look at the ignition and indeed the timing was off by 5 degrees. This made a huge difference. I would say about 30 degrees. 

d. Carburetor : Overhauled and exchanged it. Fuel flow is better, but no impact on CHTs.

e. Checked for induction leaks. Everything ok.

f. Checked grounding JPI. OK

Any other ideas, suggestions?

Conclusion:

Due to the VERY HOT weather in the NE, I have not been able to compare the results with the baseline, but I feel that the cowling mod and the timing adjustment made a difference. So at least now I feel that I can push the engine more and climb at a reasonable climb rate, even in hot weather. The CHTs on climb out at 90 degrees F go up to 450 - 460 but once established they come down to 390 - 400. 

Oscar

 

Oscar -- what are they running in cruise? I wonder if there is something we are overlooking. My F's IO-360, even on a hot summer day will never get over 390°. The big BUT is that I don't climb at Vx or even Vy. I am normally at Vy+10.

At cruise, I am seeing around 300° at altitude leaned at 100° rich of peak.

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[par]

9 minutes ago, Marauder said:

Oscar -- what are they running in cruise? I wonder if there is something we are overlooking. My F's IO-360, even on a hot summer day will never get over 390°. The big BUT is that I don't climb at Vx or even Vy. I am normally at Vy+10.

At cruise, I am seeing around 300° at altitude leaned at 100° rich of peak.

Sent from my iPad using Tapatalk

 

I usually climbout 120-130mph, which is well above Vx or Vy and there is no change. Here is another interesting observation though. On mine, if I run ROP in cruise, #3 easily goes above 400. The slightest movement as you approach peak has a very drastic change on #3 CHT...I'm talking 40 degree drop within a couple of minutes as I approach peak. I attribute all this to the carb, of course.

[Oscar Avalle]

1 hour ago, par said:

Interesting that even after throwing all this money at the problem, it didn't go away and here I thought anything could be solved by throwing enough money at it. Perhaps some more money should be thrown at the mooney?

In all seriousness though, your plane looks much better with the cowling closed up and that pointy spinner. I have the same thing on mine and obviously, I like it. As far as CHT'S go, I have noticed lately even in this 95 degree heat wave that my hottest cyl (#3) has not gone past 420 in the climbout on the first takeoff of the day. All other cylinders remain 410 or below and will quickly cool off to the mid 300's after takeoff. However, if I go for my gas stop and takeoff within 10 mins of landing, I def see #3 reach 430-450. However, this is about the worst possible case I have observed. At this point, I may look at timing when I OH the mags next annual but until then, I'm just going to live with the problem.

 

I like to close the loop on issues so let me share with you my latest experience with my CHTs. They were on the high side, in hot weather they even reached 490! So i started to look into several different solutions proposed by many of you and here are the results:

 

a. Baffling: I added the baffling around the alternator and replaced the old doghouse with a new one. Results about a reduction in 10 degrees in CHTs. 

b. Cowling: I replaced the original mod with the ARI mod. It looks nice, but the impact was lower than expected (only about 10 degrees).

 

I

 

c. Ignition: I asked my AI to look at the ignition and indeed the timing was off by 5 degrees. This made a huge difference. I would say about 30 degrees. 

d. Carburetor : Overhauled and exchanged it. Fuel flow is better, but no impact on CHTs.

e. Checked for induction leaks. Everything ok.

Any other ideas, suggestions?

Conclusion:

Due to the VERY HOT weather in the NE, I have not been able to compare the results with the baseline, but I feel that the cowling mod and the timing adjustment made a difference. So at least now I feel that I can push the engine more and climb at a reasonable climb rate, even in hot weather. 

Oscar

One thing I forgot to mention, my cowlflaps are moveable, but they are open up to the max allowable.

Thanks for the feedback. I have to say I am a bit frustrated, but then, as I mentioned I did whatever I could to solve the issue. I now believe that I have to live with it and manage it.

My climb outs will be at 120 to 130 mph and I will avoid Vx unless absolutely necessary. Once in cruise the CHTs go down significantly and hover around 380 to 410 in 80 degrees OAT and ROP. 

Oscar

[par]

Oscar, 

Do you have an engine monitor?

 

 

[Oscar Avalle]

1 hour ago, par said:

Oscar, 

Do you have an engine monitor?

 

 

Yes, I do have one.

[jamesm]

1 hour ago, Oscar Avalle said:

Carburetor : Overhauled and exchanged it

 So If I understood you correctly ... changing carburetor to  "the right carburetor.....part number is 10-3878M (M stands for Mooney)"  did not really have any adverse effect on your CHTs temps? 

I have days  where the CHT's  get to 490 dof  on CHT's (Insight G3 Engine Monitor)  almost  always on Cyl  2 &4  sometimes 3 cyl  on climb out there is not much I can do.   there doesn't seem to be any one thing  to point to for the causes of this high CHT  problem. Like you I have done checks and  looked light leaks in engine baffling  In my case with not much  success.   

Thanks for sharing your experience.

James '67C

 

 

[Oscar Avalle]

1 hour ago, Oscar Avalle said: Carburetor : Overhauled and exchanged it

 So If I understood you correctly ... changing carburetor to  "the right carburetor.....part number is 10-3878M (M stands for Mooney)"  did not really have any adverse effect on your CHTs temps? 

I have days  where the CHT's  get to 490 dof  on CHT's (Insight G3 Engine Monitor)  almost  always on Cyl  2 &4  sometimes 3 cyl  on climb out there is not much I can do.   there doesn't seem to be any one thing  to point to for the causes of this high CHT  problem. Like you I have done checks and  looked light leaks in engine baffling  In my case with not much  success.   

Thanks for sharing your experience.

James '67C

 

 

At least I know that I am not alone!!!

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